Limitations of the Farquhar–von Caemmerer–Berry Model in Estimating the Maximum Electron Transport Rate: Evidence from Four C3 Species

The study evaluates the accuracy of two FvCB model sub-models (I and II) in estimating the maximum electron transport rate for CO₂ assimilation (<i>J</i>_A-max) by comparing estimated values with observed maximum electron transport rates (<i>J</i>_f-max) in four C₃ species: <i>Triticum aestivum</i> L., <i>Silphium perfoliatum</i> L., <i>Lolium perenne</i> L., and <i>Trifolium pratense</i> L. Significant discrepancies were found between <i>J</i>_A-max estimates from sub-model I and observed <i>J</i>_f-max values for <i>T. aestivum</i>, <i>S. perfoliatum</i>, and <i>T. pratense</i> (<i>p</i> < 0.05), with sub-model I overestimating <i>J</i>_A-max for <i>T. aestivum</i>. Sub-model II consistently produced higher <i>J</i>_A-max estimates than sub-model I. This study highlights limitations in the FvCB sub-models, particularly their tendency to overestimate <i>J</i>_A-max when accounting for electron consumption by photorespiration (<i>J</i>_O), nitrate reduction (<i>J</i>_Nit), and the Mehler reaction (<i>J</i>_MAP). An alternative empirical model provided more accurate <i>J</i>_f-max estimates, suggesting the need for improved approaches to model photosynthetic electron transport. These findings have important implications for crop yield prediction, ecological modeling, and climate change adaptation strategies, emphasizing the need for more accurate estimation methods in plant physiology research.